Well according to Alex who reads things, the planning permission wossname is changing from October the 1st, so there is a good chance you don’t need it.
UPDATE: Alex has posted about how it may be worse for sheddies, it very easy for me to get confused, so hopefully, we can get a clear wossname on this
“Rules governing outbuildings apply to sheds, greenhouses and garages as well as other ancillary garden buildings… and many other kinds of structure for a purpose incidental to the enjoyment of the dwellinghouse. From 1 October 2008 outbuildings will be considered to be permitted development, not needing planning permission, subject to the following limits and conditions:
* No outbuilding forward of the principal elevation fronting a highway.
* Outbuildings and garages to be single storey with maximum eaves height of 2.5 metres and maximum overall height of four metres with a dual pitched roof or three metres for any other roof.
* Maximum height 2.5 metres within two metres of a boundary.
* No verandas, balconies or raised platforms.
* More than half the area of land around the “original house”* would be covered by additions or other buildings.
* In National Parks, the Broads, Areas of Outstanding Natural Beauty and World Heritage Sites the maximum area to be covered by buildings, enclosures, containers and pools more than 20 metres from house to be limited to 10 square metres.
* On designated land buildings, enclosures, containers and pools at the side of properties will require planning permission.
* Within the curtilage of listed buildings any outbuilding will require planning permission.
Read more at the Planning Portal.